Earplugs are a common expedient to protect ears and their sensitive structures from excessive noise and from the entry of undesired debris or other matter. Recent designs for earplugs have employed plastics. For example, U.S. Pat. Nos. 4,774,938 and 3,872,559 disclose molded plastic earplugs. Other earplug designs are set forth in U.S. Pat. Nos. 5,811,742; 5,573,015; 5,203,352; 5,188,123; and 4,434,794. Another recent effort to make foamed plastic earplugs is exemplified in U.S. Pat. No. 6,408,981. All of the above-noted patents are hereby expressly incorporated by reference for all purposes.
There remains a need in the art for a low-cost and efficient approach to the manufacture of earplugs, particularly foamed and extruded thermoplastic ear plugs. There is also a need in the art for improved earplug structures for enhancing user comfort, handling and overall earplug performance.